EGAS41 - Swansea University

41 st EGAS CP 113 Gdańsk 2009
Angular distributions of atomic photoelectrons ejected by
strong laser field
A. Bechler ∗ , M. Ślȩczka
Institute of Physics, University of Szczecin, ul. Wielkopolska 15, 70 - 451 Szczecin, Poland
∗ Corresponding author: adamb@univ.szczecin.pl ,
We consider a charged particle, initially bound by an atomic potential, which is ejected
from an atom by very short and strong laser pulses described in the dipole approximation
by the electric field. When the external field is very strong the conventional time
dependent perturbation theory cannot be used and no solution of the Time Dependent
Schödinger Equation (TDSE) can be found in a closed form without some approximations.
In this case, laser-atom interaction can be described by S-matrix formalism [1] and
Strong Field Approximation (SFA) where the Coulomb potential is taken into account
as a perturbation. We calculate direct ionization amplitude, when the electron does not
experience the binding potential, and first correction to this approximation which corresponds
to rescattering when the electron, after ionization, back to parent ion and scatters
elastically. This calculation has been performed analytically and semi-analytically. We
present angular distribution of ejected electron in the tunnelling regime. It can be observed
that for the high photon energy the angular distributions show more complicated
structure.
References
[1] H.R. Reiss, Phys. Rev. A 22, 1786-1813 (1980)
[2] D.B. Milo˘sević, G.G. Paulus, D. Bauer, W. Becker, J. Phys. B: At. Mol. Opt. Phys.
39, (2006) R203-R262
[3] S. Borbély, K. Tökési, L. Nagy, Phys. Rev. A 77, 033412 (2008)
173